Sewing machine



May 22, 1956 W. A. AYRES SEWING MACHINE Filed Jan. 25, 1954 INVENTOR. [44% 05mm 4 Ayefis lrrokw 5 2,746,408 SEWING MACHINE Waldemar A.'Ayres, Lakewood, Ohio, assignor to White Sewing Machine Corporation, Lakewood, Ohio, a corporation of Delaware Application January 25, 1954, Serial No. 465,721 .4 Claims. (Cl. 112229) with the thread carried by the needle, which bobbin is enclosed in a bobbin case removably supported upon the center pin or stud of the shuttle and retained in place by latching means. I It is usual in rotary shuttles or hooks of the type referred to to'provide a means to retain the bobbin with' n the case while placing the latter in or removing itfrom the shuttle.

Bobbin cases of the type mentioned also employ a thread tensioning means for applying a frictional force or tension upon the thread coming from the bobbin.

Where latching means, as mentioned above, is utilized upon the bobbin case the tension means ordinarily '1s prov1ded upon the side wall of the case.

This has resulted in numerous difficulties with respect to providing adequate adjustability of the tension, the conventional means being the use of a screw threaded into the side wall of the'case for effecting such adjustment. Since the side wall of the case is relatively thin very little adjustment is provided and the threads of the screw are quite delicate and hence are easily stripped. Also adjustment of such a tension means requires the use of a screw driver or similar tool and the degree of tension is not readily determinable except by trial and error.

An object of the invention is the provision of an improved thread tensioning means for a bobbin case which is of simple and inexpensive construction, yet is such that the tension may be easily adjusted without the need of tools.

A further object is the provision of an improved thread tensioning means as referred to in the preceding object and which includes means for readilyindicating the friction force or tension upon the thread for any adjusted position of the tensioning means.

Another objectis the provision of an improved thread. tensioning means which can be adjusted from the outer end of the bobbin-case when the latter is in latched assembled relation with the rotary shuttle and also is such that the means for indicating the frictional force ortension upon the thread for any adjusted position of the tensioning means can be read from the outer side of the shuttle' thus obviating the necessity of removing the bobbin case from the shuttle in order to adjust the thread tension or to determine what adjustment has been given to the thread tension.

Further and additional objects and advantages not hereinbefore referred to will become apparent hereinafter during the detailed description of an embodiment United States atent of the invention which is to follow and which embodiment is illustrated in the accompanying drawing forming part of this specification and wherein,

Fig. l is a view principally in side elevation with certain parts broken away and with other parts shown in section and illustrating the presently preferred embodiment of the improved bobbin case which is shown as provided with a lower thread bobbin and as latched in position upon a rotary shuttle or hook, only a portion of the latter being illustrated Fig. 2 is a front elevational view of the bobbin case shown in Fig. 1.

Fig. 3 is a sectional view taken substantially on line 3-3 of Fig. 2, looking in the direction of the arrows.

Fig. .4 is a view largely in elevation but partly in section and is taken substantially upon irregular line 4-4 of Fig. 1 looking in the direction of the arrows, and

Fig. 5 is a perspective view on an enlarged scale of one element of the thread tensioning means.

In Fig. 1, 10 designates a conventional rotary shuttle or hook for a sewing machine which is constructed in a well known manner and connected for rotation by the mechanism of the machine. Since this construction is well known in the art the details thereof are not here illustrated nor described.

For the present purpose it is sufiicient to note that the shuttle or hook 10 has a forwardly extending center pin. or stem 11 integral with orrigidly connected to the shuttle. The pin or stem 11 provides the 'support for a bobbin case 12 and for a thread bobbin 13 which is enclosed or nested within the case. As here shown, the bobbin case 12 is formed of metal and is generally cupshaped with a substantially planular outer face or front 14, it being noted that the planular face 14 is provided at its outer circumferential edge with a raised bead 14a where. the face 14 merges with the side wall 15 of the case. A portion of the side wall 15 is struckup therefrom in the form of an integral finger 16 which is adapted to engage'a stationary part of the machine and thereby retain the .bobbin case stationary during operation of the machine and rotation of the rotary hook or shuttle 10 as is well known in the art.

The planular face 14 of the bobbin case has a central opening in which a tubular member or sleeve 17 is positioned. This member or sleeve has fixed thereto a washer 18 engaging the inner surface of the face 14 of the case and secured thereto by brazing, welding or the like. The tubular or hollow member or sleeve 17 extends axially in both directions from the washer 13 with the portion that extends to the left, asviewed in Fig. 1, being adapted to fit within the central opening of the thread bobbin 13 and provide a support therefor, the inner end of this portion of the sleeve being received in 'an annular recess in the shuttle 1t} surrounding the" central pin or stem 11. Theclearance between the pin or stem 11 and the member or sleeve 17 is exaggerated in the drawings to facilitate identification of the parts and because the scale of the drawings is several times that of the actual mechanism.

The portion of the hollow sleeve or member 17 extending forwardly or to the right of the washer 18, as viewed in Fig. 1, projects beyond the outer surface of the face 14 of the bobbin case and is threaded for a purpose later to be explained. The face 14 of the bobbin case is provided with a latch member generally designated at 19; and which is here shown as a three-armed lever pivotally supported on the outer surface of the face 14 by a shouldered rivet 20. One arm 21 of the lever 19 provides a latch portion which is adapted to pass through. a slot or opening 22 in the tubular member 17 and engage in an annular groove 23 of the pin or stem 11 as shown in Figs. 1. and 2.

The latch member or lever 19 is normally urged to this position by a spring means 24 which is here shown as a formed from spring wire with one end engaged under an directed rearwardly'of the case adjacent the integral finger .1 6 and in a region where a portion of the side wall 15 of the case has been removed so that the angular portion of the arm 28 normally extends adjacent a flange of the thread bobbin 13 but is held spaced therefrom due tothe biasing action of the spring means 24. However, when the latch member or lever 19 is rocked against the biasing action of the spring means 24 the angular portion of the arm 28 moves into engagement with the flange of the bobbin 13 while thearm 21 of the lever 19 is moved from engagement with respectto the groove 23 of the pin 11. Consequently the bobbin case 12 is unlatched from engagement with the shuttle and the bobbin 13 is held within the case so that the bobbin does not fall from the case while the latter is being withdrawnfrom or placed upon the pin 11 of the shuttle. I

To facilitate this movement of the lever 19 it is provided with a third arm 29 which has an integral outwardly extending portiori:30 for convenient engagement by a finger or thumb of the operator, it being evident that the operator has only to' press upon the projection 30 in a counterclockwise direction as viewed in Figs. 2 and 4 to achievethe unlatching of the bobbin case and simultaneous engagement of the arm 28'with the bobbin. The construction of the bobbin case thus far set forth forms 4 no part of the present inventionand is substantially the same as that disclosed and claimed in my copending application Serial No. 246,437, filed September 13, 1951, now Patent No. 2,728,315, dated December 27, 1955.

As already stated, the front or right hand end of the sleeve 17 as viewed in Fig. 1 is externally threaded as indicated at 31 and inwardly of the threads 31 the spindle or sleeve 17 is provided with an integral external shoulder 32 or with a washer fixed thereto that engages the outer side of the base 14 of the casing. V

The cover or cap 27 is provided with a central opening through which the threaded'end of the sleeve 17 passes and said cap is held in assembled relationship on the sleeve 17 and casing 12 by a ring nut 33 screwed onto the threads 31 and located within a countersunk central portion of the cap. The cap 27 has its opposite ends of arcuate configuration with one of said ends arcuately recessed as indicated at 34. The sides of the cap 27 are straight with that side that is opposite to the flange 30 of the lever 19 being provided with an integral outwardly extending grip portion 35 for engagement by a finger or thumb of the operator when the latch member is being utilized, it being evident that the operator will place a thumb. on either the flange 30 or the portion 35 and a finger on the other of these portions to effect rocking of the lever. Suitable means is provided to prevent arcuate displacement of the cover member 27 when it is assembled on the case.

The thread tensioning means embodying the present invention comprises a spring plate or tensioning member 36 mounted on the side wall 15 of the case. This tensioning member acts on the thread from the bobbin that is brought from the interior of the bobbin case to the exterior thereof through an opening 37 in the side wall 15 of the case, which opening comprises a slot ending in a circular hole intermediate the sides of the side wall, see Fig. l.

The tensioning member 36 for the thread is a resilient, arcuate spring metal plate or member and has a radius of curvature slightly different from that of the side wall 15. The tensioning member 36 is formed of relatively thin metal and its radius of curvature is slightly less than that of the side wall 15 so that when placed thereabout the tensioning member 36 has a portion spaced from the surface of the side wall. Thistensioning member extends about a portion only of the periphery of the side wall.

The tensioning member 36 has an integral lug or tongue 38 adjacent one end which: is received in a suitable slot in the side wall 15 of the bobbin case, thus preventing circumferential shifting of the tensioning member. The

other end of the tensioning member has a relatively broad lip portion 39 extending beyond the opening 37 for the thread so that the latter may pass beneath the lip to its poin of utilization.

Adjacent the lip 39 and at one side thereof the tensioning member 36 has a second integral lug;or tongue 40 that is in the form of an angle and is receivediin a slot 41 of the side wall 15 to prevent shifting of the tensioning member from front to rear of the case. Q

The slot 41 is at substantially right angles to the slot in the side wall 15 which receives the lug 38 of the tensioning member and is substantially longer than the last mentioned slot. This enables the tensioning member 36 to be readily mounted upon the side wall 15, inasmuch as the lug 40 can first be engaged in the slot 41 and. then the tensioning member can be shifted circumferentially of the case until the lug 38 engages in its slot.

A member for holding the tensioning member 36 in position and for adjusting the tensioning effect of the member 36 on the thread is indicated generally at 42, seethe enlarged perspective view of this member in Fig. 5. The member 42 is provided with an attaching portion .43 that has an opening 44 therein adjacent its free end i and which opening can be passed over the-threaded end of the sleeve 17 and the member secured in position when the cap 27 and the nut 33 are assembled on'the bobbin case.

The attaching portion 43 of the member 42 extends substantially parallel to the face 14 of the case and has at its end remote to the opening 44 an angularly bent portion 45 which extends substantiallyparallel to the side wall 15' of thecase and engages and presses upon the outer side of the tensioning member 36. The attaching portion 43 of the member-42-adjacent to the opening 44 is provided with an integral struck-out lug 46 that bears against the outer side of the face 14 of the case, wherefore When the cover 27 and nut 33 are tightly screwed down the cover 27 will press on the portion 43 of the member 42 and move said memberdownwardly against the spring action of the lug 46 and cause the arm 45 of the member 42 to press with a spring tension against the tensioning member 36. i 1 i The member 42 can be adjustably swung about its mounting on the sleeve 17 with the result that the arm 45 of the member 42 can'be caused to bearupon the tensioning memebr 36 at various distances from the lug 38 of the member. Inasmuch as the end of the member having the lug 38 constitutes .the anchored or fulcrum end of the tensioning member 36 it will be apparent that if the member 42 is moved from a position-wherein the arm 45 thereof engages the tensioning member 36 adjacent to the lug 38 to a position wherein it is adjacent to the lug 40 that then the tensioning eflfect of. the tensioning member is increased from minimumto maximum; Of course, the converse adjustment of I the tensioning" member occurs when the member 42 is swung in the opposite direction.

It will be seen that the member 42 serves the dual purpose of holding the tensioning member in position on the side wall of the bobbin case and of adjusting the tensioning effect of the tensioning member upon the thread. It will also be seen that the member 42 can .be readily moved about thesleeve 17 to various positions of adjustthem from either. the front of the bobbin case or the side thereof'merely by the operator grasping the exposed portion of the member 42 where the arm 45 merges with the portion 43 of the member.

In order to facilitate the adjustment of the tension of the tensioning member 36 the cap 27 adjacent the edge of the arcuate recessed end 34 of the cap can be provided with suitable indicia such as the capital letters indicated in Fig. 2 which cooperate with an arrow 47 on the portion 43 of the member 42 to indicate the different adjusted positions of the member 42 from minimum to maximum thread tensioned positions, thus facilitating the proper adjustment of the device for different types of sewing. Also it will be noted that the dilferent adjusted positions of the member 42 can readily be observed by the operator from either the front of the bobbin case or from the upper side thereof.

Although a preferred embodiment of the invention has been illustrated and described herein it will be understood that the invention is susceptible of various modifications and adaptations within the scope of the appended claims.

Having thus described my invention, I claim:

1. A bobbin case adapted for use with the rotary hook or shuttle of a sewing machine and comprising a substantially cup-shaped member adapted to mount therein a thread bobbin and provided with a central sleeve adapted to extend over the post of the rotary hook or shuttle, an arcuate thread tensioning spring plate on the exterior of a portion of the wall of said member and of aradius slightly less than the radius of curvature of said wall and between which plate and said wall the thread from the bobbin is adapted to pass, and adjustable means swingably mounted coaxially of said sleeve and on said member outwardly of the bottom thereof and having a portion extending over the outer side of said plate and slidably pressing thereon and movable lengthwise of the plate to cause the plate to impart variable tensioning effects on the thread in accordance with the adjusted position of said adjustable means.

2. A bobbin case as defined in claim 1 and wherein the said portion of the wall of said member is provided with circularly spaced slotsone of which extends axially of the member and the other of which extends substantially perpendicular to said one slot, said tensioning spring plate being provided at one of its ends with a lug extending into said one slot and inwardly of but adjacent to its other end with a lug extending into the other of said slots, while said portion of said adjustable means presses on said spring plate intermediate said lugs.

3. A bobbin case as defined in claim 1 and wherein a cap is secured to said sleeve and overlies a part of said adjustable means, said cap being provided with an arcuate edge concentric to the axis of swinging movement of said means and provided with spaced indicia indicating different adjusted positions of said means calibrated in terms of thread tension, While said means is provided with an index mark cooperating with said indicia in the different adjusted positions of said means;

4. A bobbin case adapted for use with the rotary hook or shuttle of a sewing machine and comprising a substantially cup-shaped member adapted to mount therein a thread bobbin and provided with a central sleeve adapted to extend over the post of the rotary hook or shuttle, an

'arcuate thread tensioning spring plate on the exterior of a portion of the wall of said cup-shaped member and of a radius slightly less than the radius of curvature of said wall and between which plate and said wall the thread from the bobbin is adapted to pass, and adjustable means swingably mounted coaxially of said sleeve and on said cup-shaped member outwardly of the bottom thereof and having a portion extending over the outer side of said plate and slidably pressing thereon and movable lengthwise of the plate to cause the plate to impart variable tensioning effects on the thread in accordance with the adjusted position of said adjustable means, said adjustable means further including a mounting portion coaxial with said sleeve, a spring plate engaging portion extending substantially at right angles from the free end of said mounting portion and engaging said thread tensioning spring plate, and a lug struck from said mounting portion and engaging the outer side of the bottom of said cup-shaped member, and a cap member secured on said cup-shaped member outwardly of said adjustable means and pressing on the latter in a direction axially of said sleeve to flex said lug against the bottom of said cup-shaped member.v

References Cited in the file of this patent UNITED STATES PATENTS 

